Liquid-jet descaler for forging blanks



April 30, 1957 A. s. SOBEK 2,790,230 LIQUID-JET DESCALER FOR FORGING BLANKS L Filed April :5, 1953 l 2 Sheets-Sheet l r v INVEN TOR. AZFQED 6. $085k A /s' Arrow/5m LIQUID-JET DESCALER FOR FORGING BLANKS Alfred S. Sobek, Pittsburgh, Pa., assignor to Loftus Engineering Corporation, Pittsburgh, Pa., a corporation of Maryland Application April 3, 1953, Serial No. 346,578

2 Claims. (Cl. 29--81) This invention relates to apparatus for producing highvelocity liquid jets effective to remove the scale formed on forging blanks during the heating thereof. More particularly, the invention concerns the liquid-circulating system including pumps and automatic means for operating a valve controlling the liquid flow.

High-velocity liquid jets have proved effective for descaling masses of metal heated to forging or rolling temperatures. To produce such jets, a source of liquid under high pressure is required. The usual installations include large accumulators or tanks in which a column of liquid is maintained under pressure. Such tanks or chambers are costly because of the high pressure to which they are subject and the resulting liability to leakage at the joints, the prevention of which necessitates special precautions in manufacture.

I have invented apparatus for supplying liquid under the high pressure required for effective descaling, and automatically controlling it, without the use of large accumulator chambers for building up a quantity of liquid under the desired pressure. In a preferred embodiment, l employ a continuously operating high-pressure pump to deliver liquid to a plurality of nozzles directed toward the path of travel of the articles to be desc'aled, such as forging billets or blanks. I provide an electro-magnetic valve controlling the flow of liquid to the nozzles and flag switches or the like actuated by the advancing workpieces, to operate the valve so as to insure a flow of liquid from the nozzles whenever a workpiece is in position to be descaled. The system includes a primary pump drawing liquid from a sump below the nozzles and delivering it to the high-pressure pump.

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating a present preferred embodiment. In the drawings,

Fig. 1 is a plan view with parts omitted for clearness;

Fig. 2 is a vertical section taken along the plane of line II-II of Fig. 1, with parts in elevation;

Fig. 3 is a diagram of the circuit for the electromagnetic valve; and

Fig. 4 is a view showing a modification in the valves of the apparatus.

Referring now in detail to the drawings and, for the present, to Figs. 1 and 2, a descaling chamber mounted over a sump tank 11 is provided with a roller conveyor 12 and a nozzle ring 13 surrounding it. The ring 13 is fitted with a plurality of nozzles 14 directed toward the path of articles moving along the conveyor. Forging blanks or other masses of metal, after being heated to the desired temperature while passing through a furnace of any suitable type, are transferred from the furnace to conveyor 12 by an elevating flight conveyor 15. After passing through the chamber 10, the blanks pass along a red States Patent 9 delivery conveyor 16 to the forging press or other hotworking apparatus.

Descaling liquid such as water is drawn from tank 11 by a primary pump 17 through a suction or inlet line 18 and is delivered through a main delivery or discharge line 19 to the inlet of a high-pressure, multi-cylinder secondary pump 20. Pump 17 is driven by a directly connected motor 21. Pump 20 is driven by a motor 22 through V-belts and pulleys. Ring 13 is connected to the outlet of pump 20 by a discharge line 23 controlled by a solenoid shut off valve 24. A by-pass delivery line 25 connected to discharge line 23 between pump 20 and valve 24 leads to tank 11 and includes a relief valve 26. Pump 17 supplies water at low pressure such as 15 p. s. i. to pump 20, and the latter delivers water to the ring 13 at a greatly increased pressure such as 1500 p. s. i. or

" more. The flow of water from pump 20 to the ring, of

course, is controlled by electro-magnetic valve 24. Valve 26, furthermore, is adjusted to open under the discharge pressure of pump 20 when valve 24 is closed and to close when valve 24 is open. The output of pump 20 is thus continuous, being diverted to the tank 11 when not being used in descaling.

For controlling valve 24, I provide a flag switch 27 at the 'approach'or entrance to the chamber adapted to be actuated by each workpiece entering the chamber. The

' switch 27 may be a time-delay switch of known type,

arranged to hold the valve 24 open while the workpiece is moving through the descaling chamber. Alternatively, I'may provide two flag switches 27 and 28 at the entrance and exit ends, respectively, of chamber 10, adapted to be actuated by the workpieces as they enter and leave the chamber. Fig. 3 shows the circuit for the switches and the operating coil of the valve. As there shown, switch 27, when actuated by an entering workpiece, closes its contact completing a circuit for a relay 29. This relay,

' at its upper contact, completes a circuit for the valveoperating coil. At its lower contact, the relay completes a holding circuit for its own winding through the contact of switch 28 which is closed until such switch is actuated. Energiza'tion of the coil of valve 24 causes it to open. The resulting reduction of pressure in line 23 permits valve 26 to close. The latter is open, of course, so long as pump 20 is operating and valve'24 is closed. The opening of valve 24 and the closing of valve 26 cause the output of pump 20 to be delivered to the nozzle ring 13. As a result, high-velocity descaling jets are discharged from the nozzles upon the advancing workpiece.

After passing the jets and being descaled thereby, the workpiece moves out of chamber 10, and, in so doing, actuates switch 28. Switch 27, of course, opens as soon as the workpiece passes beyond it but this does not affect valve 24 since relay 29 maintains the circuit (through closed switch 28 and the lower contacts of relay 29) for the valve coil and its own winding. When the workpiece strikes switch 28, however, the latter opens the holding circuit for the relay winding, and the relay immediately drops out, thus opening the circuit of the valve coil. The valve then closes by virtue of a restoring spring therein,

and the pressure in line 23 then builds up until valve 26 opensv to bypass the output of the pump back to the tank 11/ V e 1 Should the workpieces follow each other in close-order succession, as will usually be the case, valve 24 will be kept open continuously. Thus if several workpieces are in chamber 10 at the same time, the one about to leave will not cause closure of valve 24 as explained above, because the one entering will maintain energization of the valve coil by closing switch 27. If desired, the relay 29 may be of the slow-release type to insure descaling of the last few workpieces of a series since otherwise, the

first operation of switch 28 piece would close valve 24.

In cases where the intervals between the successive descaling operations are relatively great, it will be understood that the motors 21 and 22 of the pumps will be working against the; pressure head of the spring loaded valve 26, a pressure head of 1500 pounds or more per square inch in the illustrated embodiment of the invention. In order to eliminate or minimize the consequent waste of electric power required to operate the pump motors 21 and 22 under such circumstances, I illustrate in Fig. 4 a solenoid valve 39 arranged in a by-pass line 30 around valve 26. The valve 39 is a solenoid valve which stands in open position when the solenoid valve 24 is closed, wherebyduring the fidle operational? thepumps 17 and 20 the water iscirculated against practicallyno head! When, a. workpiece enters thc descaling chamber and operates the flag. switch 27, the relay29 operates to close. theIvalve 39 simultaneously .=with the opening. of

the valve 24, it being understood thatthe terminals of the solenoids of both valves 24 and 39 aretonnected in parallel with upper contacts of relay29. In the event that the solenoid valve 39 should stick or fail to open, the relief valve 26 will open and prevent damage to the pumps or motors. Alternately, or supplementarily, the motors 21 and 22 may have circuit-breakers arranged to open and interrupt operation in thefevcnt the relief valve fails to open and overload the motors.

It will'be apparent from the foregoing that the invention provides a simple and relatively inexpensive system for circulating descaling liquid continuously from a sump to nozzles dischargingon the work. By using a low-pressure suction pump feeding water to the secondary or high-pressure pump, I avoid the necessity for costly accumulators and, at the same time, am able to maintain a continuing supply of liquid, whereas the capacity of an accumulator is'limited. p

Although I have described in detail only a preferred embodiment, changes therein may be made without departing from the spirit of the invention or the scope of the appended claims.

I'claim: f J

1. Apparatus for descaling heated masses of metal comprising in combination means for conveying scalebearing hot masses offmetal along a predetermined path,

nozzles mounted for discharging violent scale-removing jets'of liquid upon. the metalmasses moving along said path, a sump for collecting liquid discharged bysaid nozzles, aprimary pump and a secondary pump each having an inlet and outlet, the inlet of said primary pump communicating with the liquid in said sump and the outlet of said primary pump communicating with the inlet of the secondary pump, a main delivery line leading from the outlet of the secondary pump to said nozzles, a by-pass delivery line connected for the delivery of liquid from the outlet of said secondary pump to said sump, a motor connected to drive said primary pump for delivering liquid from said sump to the inlet of said secondary pump at a pressure of relatively low value, a motorconnected to drive said secondary pump for delivering liquid to said delivery lines at a pressure increased from said relatively low value produced by said primary pump to a value at least equal to the jet-producing pressure required at said nozzle a shut-off valve in said main delivery line between said secondary pump and said nozzles, a pressure-relief valve in said by-pass delivery line loaded for closing and remaining closed,

after the entry of the last while said shut-01f valveis open and liquid is flowing through said main delivery line to said nozzles, and for opening and remaining open while said shut-off valve is closed with said pumps in operation, means responsive to the hot masses moving along said path for opening and closing said shut-off valve, with the consequent closing and opening, respectively, of said pressure-relief valve, whereby said pumps deliver liquidat substantially jetproducing pressure both when said jets are in operation and; when they are not. a

2. Apparatus for descaling heated masses of metalcomprising in combination means for conveying scale-bearing hot masses of metal along apredetermined path, nozzles mounted for discharging violent scale-removing jets of liquid upon the metal masses moving along said path, a sump for collecting liquid discharged by said nozzles, a primary pump and a secondary pump each having an inlet and outlet, the inlet of said primary pump compass delivery line connected for the delivery of liquid energizing circuit respectively to open and close said shut from the outlet of said secondary pump to said sump, amotor connected to drive said primary pump for delivering liquid from said sump to the inlet of said secondary pump at a pressure of relatively low value, a motor connected to drive said secondary pump for delivering liquid to said delivery lines at a pressure increased from said relatively low value produced by said primary pump to a value at least equal to the jet-producing pressure required at said nozzles, a shut-off valve in said main delivery line between said secondary pump and said nozzles, a pressure-relief valve in said by-pass delivery line loaded for closing and'remaining closed, while said shut-cit valve is open and liquid is flowing through said main delivery line to said nozzles, and for opening and remaining open w'hiie saidshu't-ofi valve is closed with said pumps in operation, means comprising an electric solenoid for operatingfsaid shut-off valve, an energizing circuit for said solenoid, flag-switch means responsive to the-hot masses moving along said path for closing and opening said otfvalve, with the consequent closingand opening, respectively, of said pressure-relief valve, whereby said pumps deliver liquid at substantially jet-producing pressure both when said jets are in'operation and when they are not.

References Cited in the file of this patent V UNITED STATES 1,145,671 Butcher July 6, 1915 1,398,818 Upp Nov. 29, 1921 1,886,581 Pitts Nov. 8, 1932 1,917,350 Wolf July 11, 1933 2,085,303 Ernst June 29, 1937 2,194,054 Peterson Mar, 19,1940 2,289,967 Johnson ct al July 14, 1942 2,394,514 Evans 'et al. Feb. 5, 1946 2,440,134 Zademach et al. Apr. 20, 1948 2,532,856 Ray Dec. 5, 1950 OTHER REFERENCES 1 Publication, Descaling Steel by Spray System, by R. 

